Air-breathing direct methanol fuel cells with catalysed titanium mesh electrodes

The conventional electrode structure used in the DMFC is generally based on porous carbon-based gas diffusion electrodes, which consists of a catalyst layer, hydrophobic microporous layer and carbon paper or cloth. This structure is not ideal for transport and release of CO2 gas produced during methanol oxidation at the anode, potentially resulting in considerable hydrodynamic and mass transport limitations. To circumvent these problems, an expanded titanium mesh has been adopted as the catalyst substrate material in this study. Titanium mesh was used as the substrate due to its chemical stability and its ability to support a diverse range of electrocatalysts. In the proposed fuel cell application, the mesh-based electrode has several potential advantages in terms of cost, simplicity, size and shape. This work describes the design, fabrication and evaluation of a passive air-breathing direct methanol fuel cell using the mesh-based electrodes. PtRu/Ti and Pt/Ti prepared by electrodeposition onto the Ti mesh were used as anode and cathode, respectively. Methanol is stored in an in-built reservoir and oxygen is taken from the surrounding air. Single cells with an active area of 9 cm2 produced a power density of 9.5 mW cm-2, whereas a cubic four-cell stack with an active area of 24 cm2 produced a maximum power of 180 mW. The effects of experimental parameters such as concentration and temperature on the cell performance were also investigated. © 2009 Nova Science Publishers, Inc. All rights reserved.